Jon’s Column September 2017

September 13, 2017

Our hottest winter for decades. And as we move into spring proper still no rain to maintain any beneficial soil moisture.

As the soil dries it may well become what is called hydrophobic. That is it can actually repel water. The water will just lay on the surface and not mix with the soil particles. This is due to a build up of waxy residues that remain after organic matter breaks down and most often effects fine sandy soils or soil that contain a high percentage of the fine sand. (It can also occur in old dry potting blends.)

The outcome is that although you water the soil, no moisture reaches the root zone and the plants become stressed.

By applying soil wetting agents or re wetting agents, even seaweed solutions, the waxy residues will break down and dissolve allowing moisture to penetrate.

The addition of a good quality organic compost tilled lightly into the soil surface will also improve this condition by allowing the soil microbes to play their role in maintaining good soil health.

For added protection against further heat stress apply a good 100mm of quality organic mulch such as cane mulch.

For deep watering around your larger shrubs etc, you can purchase a deep watering wand or spike that attaches to the hose and pushed into the soil to a depth of 60cm thus allowing water to get to the deeper root systems. I find this devise very useful around my mature hibiscus and Lillypillies.

At this time of the year a lot of gardeners will be taking cuttings of various plants so here are a few tips on plant propagation.

Take your cuttings in the coolest part of the day and cover with a wet cloth or newspaper.

Use sharp, clean secateurs when making the final cut. Always use a sterile propagation soil medium. Avoid the use of potting soils, they are generally not suitable for cuttings. Always use a cutting compound or gel suitable for the type of wood, e.g. soft wood, medium or hardwood cuttings.

When using hormonal cutting powders, remember less is best. Put some powder into a shallow container such as a lid from a jar. Dip the cutting into the powder then tap the cutting to remove excess powder and use a dibber (a pencil is good) to form the hole in the mix, insert the cutting and firm down just enough to make the cutting stay upright. (At this stage I generally mist the cutting using my one litre spray bottle.) You can put more than one cutting into the propagating container if there is room).

If your cuttings still have leaf attached, use sharp scissors to cut the leaf in half at its widest point. This will help the leaf remain ridged on the stem.

For some plant species gardeners will use a biodegradable pot made of compressed organic matter. That way when the cutting has struck, the whole thing can be planted in the garden without any disturbance to fresh root system.

The seed company ‘Mr Fothergills’ produce compressed biodegradable pots in various sizes, under the name ‘Jiffy Pots’. They also make compressed peat pallets that swell up when immersed in water for seed production. Ideal for seed that may well be difficult to prick out of a seed bed. You just plant the whole thing.

Also in the range of propagation products are seed raising trays complete with lids and vents that protect and maintain the correct humidity for small cuttings and seeds.

Most of the tray types are reusable, however I recommend you wash and clean the trays after each use.

If you are new to gardening or just want some advice on propagation methods, come to the garden centre or ring and make a time for our team to be available for you for answers and advice.